Using Mahjong Tiles to Generate a Dark Jungle Sandbox

August 18, 2011

I had been planning to put the Dark Jungle on hexes for awhile but I didn’t think it would be all that interesting of a map, because from one perspective it’s just a massive expanse of jungle canopy. To spice things up I designed a system of generating a Dark Jungle map with encounters and obstacles using Mahjong tiles. I’ve customized this system for the dragon-hunting Jungle Men campaign, so lots of monsters to hunt and changes in wind direction to aid or hinder the hunters.

Everybody has a set of Mahjong tiles and can interpret Chinese characters, right? (Unfortunately, I haven’t memorized the Chinese characters yet, so I need a chart for reference.)

A Mahjong set contains 144 tiles, many of which have jungle-themed icons, so it’s a natural fit for jungle hijinks. Different sets contains different variations of some icons, but here is a good example with jungle-themed icons:

Generating a Dark Jungle sandbox is a simple matter of pulling a tile for each hex when creating a map before play begins. (The Jungle Event System is used to determine wandering monsters and random events during play.) Or, for less encounter density, roll d6 for each hex: on a 1 pull a tile to determine hex contents. 2-6 indicates “regular” Dark Jungle terrain and no tile is drawn.

In a complete mahjong set there are four copies of most of the tiles, with eight unique tiles. Here’s a breakdown of tile counts and what they indicate when generating a Dark Jungle hex:

If a Character tile is drawn, there is a chance that the indicated Jungle Man or Bolo Man is encountered. Roll d10. If the roll is equal to or less than the NPC’s value (1-9 on the chart), then the NPC is placed in this hex. If the roll is greater than the NPC’s value, then the hex contains a Spindle River instead. After an NPC is placed in a hex, any time its tile is later drawn the hex contains a Fire Ravine instead. If NPC’s fourth tile drawn and that NPC hasn’t been placed yet, then the NPC is automatically placed in this hex.

The purpose of this system is to make some NPCs more likely to be found far away from where the PCs enter the Dark Jungle. Similarily, rivers will be common when the PCs first enter the Dark Jungle, but Fire Ravines will become prevalent deep in the interior. This dice-rolling mechanic could also be applied to Circle and Bamboo tiles if you prefer to have less monsters or to make some monsters rarer than others.

Spindle River
These swirling rivers lace the Dark Jungle. They often flow in unnatural directions, sometimes flowing underground and resurfacing later. Crossing a spindle river is dangerous due to its swift and swirling current, but not impossible. Some of the bravest or foolish have been known to ride rafts or canoes for rapid downstream travel, but it’s a good idea get off before the river plunges back underground or into a Fire Ravine. Use the following guidelines to generate a spindle river:

When a Spindle River hex is created, roll d6 to determine where the river exits the hex and/or another d6 to determine where it enters the hex. If both rolls are the same, reroll until they are different.

Continue chaining sections (hexes) of river on each end of the river according to the above method. Note that the river may loop back into hexes that it already passes through, even passing through a single hex side multiple times. Best to use pencil when initially generating river section so adjustments can be made to allow a river to pass through a hex multiple times.

The river ends when the hex side indicated by the die roll cannot be reached due to a barrier in the hex, such as another section of river, Fire Ravine, etc. Spindle Rivers never fork or intersect. For example, let’s say River “A” enters a hex from a southern hex side and that hex already contains River “B” crossing it from east to west. If the next die roll indicates a northerly flow, then it is blocked by River “B” and so River “A” ends in this hex (enters a cave, pit, etc.).

After the river is completely drawn, decide the direction of flow. The only rule for this is if the river is terminated by a Fire Ravine, then the river flows into the ravine to form an incredible waterfall and plume of steam. Only one end of a river can flow into a fire ravine, obviously.

Fire Ravine
These are steep canyons with flame and lava bubbling far below. Fire Ravines vary in width, typically from 3 to 60 feet wide (3d20). Fire ravines are difficult to cross, of course, but some can be crossed by swinging on vines if you are willing to endure a blast of scorching heat. Lung Eatin’ Hayes is famous for his flight across a wide ravine on the back of a panther. Use the following guidelines to generate a Fire Ravine:

When a Fire Ravine hex is created, roll d6 to determine how long it is. If the length is greater than one, perform the next step.

From the initial Fire Ravine hex, chain additional hexes in a straight line until the length is attained. Whereas Spindle Rivers bend and meander, Fire Ravines are always straight, though sometimes multiple ravines will intersect from different directions.

If you wish for a Fire Ravine to intersect an existing Spindle River, then the river flows into the ravine. If that splits the existing river in two, then the river flows into the ravine from both directions.

Dragon Tiles
Dragons are the primary quarry of Jungle Men. Dragons in the Dark Jungle are not the bat-winged behemoths of high fantasy, but more like the typical portrayal of oriental dragons. Entering a dragon hex and hunting it should be an adventure of itself. In the Dark Jungle they are typically one of three colors:
Red: The smallest and most devious. Its scales are very rough, almost thorny.
Green: The most intelligent and poisonous. Its scales have an iridescent appearance.
White: The largest and most ferocious. Its scales have a slick, almost wet appearance.

Wind Tiles
The Dark Jungle exhibits an interesting wind phenomena. Though separated from the atmosphere by a thick layer of leaf, limb, and vine, winds ranging from persistent gusts to sudden zephyrs are felt underneath the canopy. Natives believe them to be breath of dragons. High Wizards from the east attribute the wind to the incredible amount of decomposition that occurs in the Dark Jungle. Some poets have, in so many elegant words, theorize that the winds are due to rotating air masses within the sub-atmosphere between the jungle canopy and floor.

Wind direction changes when the PCs enter a hex with a Wind tile . For example, when a North Wind tile is encountered, the Wind blows out of the north. Wind direction persists until another wind hex in entered.

If the PCs are downwind of monsters, they have a better chance of detecting the monsters before the monsters detect them. If the PCs are moving directly into the wind, they have a 4 in 6 chance of surprising any monsters encountered. (Diagonal movement on a hex map qualifies as movement in two directions for purposes of determining surprise. For example, with a wind from the west the surprise advantage is also granted for movement through the NW and SW sides of the hex just exited.)

Flower and Season Tiles (Special Locations)
There are eight unique tiles: four Flowers and four Seasons. When one these is pulled, a unique special location is found in the hex:

[…] The following is the partial script of a freestyle PBEM jungle adventure played with a friend last year. Complete with arcade sound effects. It introduced El Grande Loco, an NPC mentioned in the Dark Jungle Sandbox Generation system. […]

[…] This must be declared before the Who Has Been Detected? roll is made. The Distance becomes 3. The Dark Jungle generation system includes a wind direction feature, or any other method of determining the current wind direction […]

Fire in the Jungle is…

An exploration of the green, dark green, bloody green, black, burnt, and ashen. The content of this blog consists primarily of two things: 1) Descriptions of the fantasy jungle setting I've created for rpgs. 2) Notes on some of the books, movies, etc. that have influenced that fantasy setting.